728731 has 2 divisors, whose sum is σ = 728732. Its totient is φ = 728730.

The previous prime is 728729. The next prime is 728743. The reversal of 728731 is 137827.

728731 = 346² + 347² + ... + 351².

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (137827) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 728731 - 2¹ = 728729 is a prime.

It is a super-2 number, since 2×728731² = 1062097740722, which contains 22 as substring.

Together with 728729, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 728731.

It is not a weakly prime, because it can be changed into another prime (728701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 364365 + 364366.

It is an arithmetic number, because the mean of its divisors is an integer number (364366).

2⁷²⁸⁷³¹ is an apocalyptic number.

728731 is a deficient number, since it is larger than the sum of its proper divisors (1).

728731 is an equidigital number, since it uses as much as digits as its factorization.

728731 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2352, while the sum is 28.

The square root of 728731 is about 853.6574254348. The cubic root of 728731 is about 89.9889286793.

The spelling of 728731 in words is "seven hundred twenty-eight thousand, seven hundred thirty-one".